Amperometric methylene green-mediated pyruvate electrode based on pyruvate oxidase entrapped in carbon paste

✍ Scribed by Juozas Kulys; Lizhong Wang; Nomeda Daugvilaite

• Book ID: 102980685
• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 566 KB
• Volume: 265
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(92)85149-z

✦ Synopsis

An amperometrlc electrode sensitive to pyruvate based on methylene green as mediator and on carbon paste chemically modtiled with pyruvate oxldase IS described The electrode generates an anodlc current m the range 0 O-O 5 V vs SCE The optunum pH IS 7 0 The apparent Mlchaehs constant, Ktiappj, for the cahbratlon graphs for the electrode depends on the amount of pyruvate oxldase and changes m the range 12-l 6 mM at a phosphate concentration of 0 1 M The electrode sensltlvlty achieved is 518 PA 1 mmol-' cm-* and does not depend on the normal oxygen concentration m solution The electrode responds to morgamc phosphate, and Km_,,,) was 87 mM at a pyruvate concentration of 2 1 mM The electrodes were used for the determination of pyruvate m human sweat The electrodes remained stable for more than 2 months Keywords Amperometry, Enzymatic methods, Enzyme electrode, Pyruvate F'yruvate 1s formed as an intermediate product m sugar metabolism and enzymatic carbohydrate degradation The level of pyruvate, m addition to those of glucose and L-lactate, m blood 1s related to diabetes melhtus, and for this reason biological mformatlon concerning this metabohte 1s required [ll In muscle, during exertion pyruvate derived from glycogen 1s reduced to L-lactic acid, which 1s reoxldlzed and partially reconverted mto glycogen during rest The pyruvate concentration m human or horse blood or sweat durmg physical exercise can indicate the intensity of metabolism Correspondence to J Kulys, Institute of Blochemstry, Llthuaman Academy of Sciences, 2600 Vllnms (Llthuama) ' On leave from the Department of Pharmaceutical Analysis, Guangdong Medlcal and Pharmaceutical College, Guandong, China